Adhesive cementation of zirconia posts to root dentin: evaluation of the mechanical cycling effect.
This study evaluated the effect of mechanical cycling on the bond strength of zirconia posts to root dentin. Thirty single-rooted human teeth were transversally sectioned to a length of 16 mm. The canal preparation was performed with zirconia post system drills (CosmoPost, Ivoclar) to a depth of 12 mm. For post cementation, the canals were treated with total-etch, 3-steps All-Bond 2 (Bisco), and the posts were cemented with Duolink dual resin cement (Bisco). Three groups were formed (n = 10): G1 - control, no mechanical cycling; G2 - 20,000 mechanical cycles; G3 - 2,000,000 mechanical cycles. A 1.6-mm-thick punch induced loads of 50 N, at a 45 degrees angle to the long axis of the specimens and at a frequency of 8 Hz directly on the posts. To evaluate the bond strengths, the specimens were sectioned perpendicular to the long axis of the teeth, generating 2-mm-thick slices, approximately (5 sections per teeth), which were subjected to the push-out test in a universal testing machine at a 1 mm/min crosshead speed. The push-out bond strength was affected by the mechanical cycling (1-way ANOVA, p = .0001). The results of the control group (7.7 +/- 1.3 MPa) were statistically higher than those of G2 (3.9 +/- 2.2 MPa) and G3 (3.3 +/- 2.3 MPa). It was concluded that the mechanical cycling damaged the bond strength of zirconia posts to root dentin.
Galhano
Graziela Avila
GA
Dept. of Dental Materials and Prosthodontics, School of Dentistry of São José dos Campos, São Paulo State University, São José dos Campos, SP, Brazil. grazielagalhano@yahoo.com.br
Melo
Renata Marques de
RM
Pavanelli
Carlos Augusto
CA
Baldissara
Paolo
P
Scotti
Roberto
R
Valandro
Luiz Felipe
LF
Bottino
Marco Antonio
MA
D000704:Analysis of Variance; D002516:Ceramics / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods*; D003799:Dental Stress Analysis / Q000379:methods; D003804:Dentin / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D011176:Post and Core Technique / Q000295:instrumentation* / Q000592:standards; D019279:Resin Cements / Q000737:chemistry*; D018915:Root Canal Preparation; D013314:Stress, Mechanical; D013718:Tensile Strength; D015040:Zirconium / Q000737:chemistry*
D019279:Resin Cements; D015040:Zirconium; C028541:zirconium oxide